Is it permissible to be mechalel Shabbos to save the life of an animal, such as a family pet?
Could minchag, chumras, and/or purely Rabbinical prohibitions be relaxed in such a situation, and to what extent?

Please assume no Gentile is available to save the animal's life. However, if it would be permissible to relax certain rules in order to summon a Gentile for this purpose, please discuss.

+1. I have a crazy family story about this; in short, someone asked my father (a people doctor) about a rabbit whose life was in danger....we asked the rabbi, who said to ask a non-Jew to take it to the veterinary hospital. (the rabbit, unfortunately, didn't make it)
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ShokhetNov 30 '14 at 17:28